Yes, this Form 1099-R is correct, reporting a distribution of the $8,000 excess elective deferral plus $1,600 of attributable earnings. The entire amount is taxable on your 2020 tax return. Your W-2 from this employer should still show the $8,000 as part of your elective deferral that is excluded from box 1 and included in box 12 with code D, so none of this money is taxed twice.
